Light-emitting element, display device, and method for producing light-emitting element

Abstract

A light-emitter including: a transparent first electrode; a charge injection transport layer; a light-emitting layer; and a transparent second electrode, layered in this order. The light-emitting layer is defined by a bank. The charge injection transport layer has a recessed structure including: an inner bottom surface in contact with a bottom surface of the light-emitting layer; and an inner side surface continuous with the inner bottom surface. The inner side surface includes: a lower edge continuous with the inner bottom surface; and an upper edge continuous with the lower edge. The upper edge is aligned with a bottom periphery of the bank, or has contact with a bottom surface of the bank. The charge injection transport layer has contact with a side surface of the light-emitting layer.

The invention claimed is: 
     
       1. A double-sided light-emitter that emits light from both sides thereof, comprising:
 a first electrode; 
 a charge injection transport layer; 
 a functional layer including a light-emitting layer; and 
 a second electrode, the first electrode, the charge injection transport layer, the functional layer and the second electrode being layered in this order, at least the light-emitting layer being defined by a bank, wherein 
 the first electrode and the second electrode are transparent electrodes, 
 at least a surface of the bank is liquid-repellent, and the charge injection transport layer is composed of a metal compound that is more liquid-philic than the surface of the bank, 
 the charge injection transport layer has a recessed structure so that in a region defined by the bank, the charge injection transport layer is lower than a bottom surface of the bank, 
 the recessed structure of the charge injection transport layer includes:
 (i) an inner bottom portion having an inner bottom surface that is in contact with a bottom surface of the functional layer; and 
 (ii) an inner side portion having an inner side surface that is continuous with the inner bottom surface, and 
 
 the inner bottom portion has a smaller film thickness than the inner side portion. 
 
     
     
       2. The light-emitter of  claim 1 , wherein
 the charge injection transport layer is a hole injection layer made from one of a metal oxide, a metal nitride, and a metal oxynitride. 
 
     
     
       3. The light-emitter of  claim 2 , wherein
 the functional layer includes a hole transport layer that transports holes from the hole injection layer to the light-emitting layer, and 
 the hole transport layer is interposed between the hole injection layer and the light-emitting layer. 
 
     
     
       4. The light-emitter of  claim 1 , wherein
 the transparent electrodes are made from ITO or IZO. 
 
     
     
       5. The light-emitter of  claim 1 , wherein
 a metal thin film that is semi-transparent or transparent is layered on either or both the first electrode and the second electrode. 
 
     
     
       6. The light-emitter of  claim 5 , wherein
 the metal thin film contains any material selected from the group consisting of Ag, Mg, Al, Pt, Pd, Au, Ni, Ir and Cr, and has a thickness falling within a range of 3 nm to 30 nm. 
 
     
     
       7. The light-emitter of  claim 1 , wherein
 the recessed structure is cup-like shaped. 
 
     
     
       8. The light-emitter of  claim 1 , wherein,
 in the region defined by the bank, the charge injection transport layer having the recessed structure is lower than a bottom periphery of the bank and aligned with the bottom periphery of the bank. 
 
     
     
       9. The light-emitter of  claim 1 , wherein,
 the light-emitting layer includes a layer containing a high-polymer material. 
 
     
     
       10. The light-emitter of  claim 1 , wherein
 the charge injection transport layer extends along the bottom surface of the bank to an adjacent pixel. 
 
     
     
       11. A display apparatus, comprising a plurality of the light-emitter of  claim 1 . 
     
     
       12. A double-sided light-emitter that emits light from both sides thereof, comprising:
 a first electrode; 
 a charge injection transport layer; 
 a functional layer including a light-emitting layer; and 
 a second electrode, the first electrode, the charge injection transport layer, the functional layer and the second electrode being layered in this order, at least the light-emitting layer being defined by a bank, wherein 
 the first electrode and the second electrode are transparent electrodes, 
 at least a surface of the bank is liquid-repellent, 
 the charge injection transport layer includes:
 (i) a metal compound that is dissolvable by a predetermined solvent; and 
 (ii) a recessed portion where the metal compound has been dissolved by the predetermined solvent, 
 
 the recessed portion of the charge injection transport layer includes:
 (i) an inner bottom portion having an inner bottom surface that is in contact with a bottom surface of the functional layer; and 
 (ii) an inner side portion having an inner side surface that is continuous with the inner bottom surface and in contact at least with a portion of a side surface of the functional layer, and 
 
 the inner bottom portion has a smaller film thickness than the inner side portion. 
 
     
     
       13. The light-emitter of  claim 12 , wherein
 the charge injection transport layer is a hole injection layer made from one of a metal oxide, a metal nitride, and a metal oxynitride. 
 
     
     
       14. The light-emitter of  claim 13 , wherein
 the metal oxide comprises one of an oxide of tungsten and molybdenum. 
 
     
     
       15. The light-emitter of  claim 13 , wherein
 the functional layer includes a hole transport layer that transports holes from the hole injection layer to the light-emitting layer, and 
 the hole transport layer is interposed between the hole injection layer and the light-emitting layer. 
 
     
     
       16. The light-emitter of  claim 12 , wherein
 the transparent electrodes are made from ITO or IZO. 
 
     
     
       17. The light-emitter of  claim 12 , wherein
 a metal thin film that is semi-transparent or transparent is layered on either or both the first electrode and the second electrode. 
 
     
     
       18. The light-emitter of  claim 17 , wherein
 the metal thin film contains any material selected from the group consisting of Ag, Mg, Al, Pt, Pd, Au, Ni, Ir and Cr, and has a thickness falling within a range of 3 nm to 30 nm. 
 
     
     
       19. The light-emitter of  claim 12 , wherein
 the charge injection transport layer is liquid-philic, and the bank is liquid-repellent. 
 
     
     
       20. The light-emitter of  claim 12 , wherein
 the predetermined solvent is at least one of a developing solution for removing a part of a resist film used to form the bank and a cleaning fluid for cleaning residuals of the resist film remaining after formation of the bank. 
 
     
     
       21. A method of manufacturing a light-emitter, comprising:
 forming a first electrode on a substrate, the first electrode being a transparent electrode; 
 forming, above the first electrode, a thin film including a metal compound that is dissolvable by a predetermined solvent; 
 forming a bank on the thin film by forming a resist film including a resist material on the thin film and etching the resist film with a developing solution, at least a surface of the bank being liquid-repellent; 
 forming, after the bank is formed, a charge injection transport layer by cleaning residuals of the resist film that adhere to the thin film with a cleaning fluid and dissolving a part of the thin film with the cleaning fluid, the charge injection transport layer including a recessed portion, the recessed portion including an inner bottom portion having an inner bottom surface and an inner side portion having an inner side surface that is continuous with the inner bottom surface; 
 forming a functional layer by coating the inner bottom surface of the charge injection transport layer and the inner side surface of the charge injection transport layer with ink drops deposited into a region partitioned by the bank and drying the ink drops; and 
 forming a second electrode above the light-emitting layer, the second electrode being a transparent electrode, wherein 
 the inner bottom portion has a smaller film thickness than the inner side portion. 
 
     
     
       22. The method of  claim 21 , wherein
 the charge injection transport layer is a hole injection layer made from one of a metal oxide, a metal nitride, and a metal oxynitride. 
 
     
     
       23. The method of  claim 22 , wherein
 the functional layer includes a hole transport layer that transports holes from the hole injection layer to the light-emitting layer, and 
 the hole transport layer is interposed between the hole injection layer and the light-emitting layer. 
 
     
     
       24. The method of  claim 21 , wherein
 the transparent electrodes are made from ITO or IZO. 
 
     
     
       25. The method of  claim 21 , wherein
 a metal thin film that is semi-transparent or transparent is layered on either or both the first electrode and the second electrode. 
 
     
     
       26. The method of  claim 25 , wherein
 the metal thin film contains any material selected from the group consisting of Ag, Mg, Al, Pt, Pd, Au, Ni, Ir and Cr, and has a thickness falling within a range of 3 nm to 30 nm. 
 
     
     
       27. A method of manufacturing a light-emitter, comprising:
 forming a first electrode on a substrate, the first electrode being a transparent electrode; 
 forming, above the first electrode, a thin film including a metal compound that is soluble in a predetermined solvent; 
 forming a bank on the thin film by forming a resist film including a resist material on the thin film and etching the resist film with a developing solution, at least a surface of the bank being liquid-repellent; 
 forming a charge injection transport layer by cleaning residuals of the resist film that adhere to the thin film and dissolving a part of the thin film with the developing solution, the charge injection transport layer including a recessed portion, the recessed portion including an inner bottom portion having an inner bottom surface and an inner side portion having an inner side surface that is continuous with the inner bottom surface; 
 forming a functional layer by coating the inner bottom surface of the charge injection transport layer and the inner side surface of the charge injection transport layer with ink drops deposited into a region defined by the bank and drying the ink drops; and 
 forming a second electrode above the functional layer, the second electrode being a transparent electrode, wherein 
 the inner bottom portion has a smaller film thickness than the inner side portion. 
 
     
     
       28. The method of  claim 27 , wherein
 the charge injection transport layer is a hole injection layer made from one of a metal oxide, a metal nitride, and a metal oxynitride. 
 
     
     
       29. The method of  claim 28 , wherein
 the functional layer includes a hole transport layer that transports holes from the hole injection layer to the light-emitting layer, and 
 the hole transport layer is interposed between the hole injection layer and the light-emitting layer. 
 
     
     
       30. The method of  claim 27 , wherein
 the transparent electrodes are made from ITO or IZO. 
 
     
     
       31. The method of  claim 27 , wherein
 a metal thin film that is semi-transparent or transparent is layered on either or both the first electrode and the second electrode. 
 
     
     
       32. The method of  claim 31 , wherein
 the metal thin film contains any material selected from the group consisting of Ag, Mg, Al, Pt, Pd, Au, Ni, Ir and Cr, and has a thickness falling within a range of 3 nm to 30 nm.